In a photolithography of a semiconductor device manufacturing process, a resist pattern is formed on a semiconductor wafer (hereinafter, referred to as a “wafer”) as a substrate using a resist pattern forming system including a coating/developing apparatus and an exposing apparatus which are connected to each other. The coating/developing apparatus includes liquid treatment modules which supply various kinds of chemical liquids, for example, a resist coating module which coats a resist on the wafer to form a resist film on the wafer, a developing module which supplies a developing solution onto the resist film exposed by the exposing apparatus to form a resist pattern, and a protective film forming module which supplies a chemical liquid onto the wafer to form a protective film for protecting the resist film when the wafer is exposed by the exposing apparatus, and the like. The coating/developing apparatus also includes a heating module which performs a heat treatment on the wafer before and after respective liquid treatments. An example of such a coating/developing apparatus is known.
In recent years, throughput of the exposing apparatus becomes increasingly higher. Thus, improvement of throughput of the coating/developing apparatus requires enhancing productivity of the resist pattern forming system. Specifically, the coating/developing apparatus is required to process, for example, about 275 sheets of wafers per hour. To do this, increasing the number of modules which perform the same type of treatments on the wafer and performing respective treatments on the wafer in these modules in parallel may be considered.
As an example, there is known a coating/developing apparatus provided with a front processing block and a rear processing block which are sequentially arranged to face an exposing apparatus. Each of the front and rear processing blocks includes unit blocks which are vertically partitioned in multiple-stages. Each of the unit blocks includes a processing module, a heating module, and a transfer mechanism for transferring a wafer between these modules. Such an arrangement facilities installation of various types of additional modules. In the rear processing block, a protective film forming module is installed in a lower one of the unit blocks, and a rear surface cleaning module which cleans a rear surface of the wafer before exposure is installed in an upper unit block. Together with the protective film forming module and the rear surface cleaning module, two cups for processing wafers received therein are arranged along the direction in which the front and rear processing blocks are arranged.
In such a coating/developing apparatus, a wafer (wafer after exposure) which has been subjected to an exposure treatment by the exposing apparatus passes through the rear processing block, and then is transferred to the front processing block where the wafer is subjected to respective treatments. As described above, when the protective film forming module and the rear surface cleaning module are installed in the rear processing block, a transfer mechanism installed in each of the unit blocks of the rear processing block is sometimes required to transfer the wafer after exposure in the course of transferring a wafer before exposure to a respective module. This increases a load borne by the transfer mechanism, which makes it difficult to sufficiently enhance throughput.
Meanwhile, the rear surface cleaning module may be installed in an interface block which interconnects between the rear processing block and the exposing apparatus. However, if the rear surface cleaning module is installed in the interface block, an occupied floor area (footprint) of a subsequent stage of the processing block is relatively large with respect to the number of the cups installed in the rear processing block. Thus, the coating/developing apparatus is required to have an increased number of additional modules while suppressing the footprint. That is to say, there is a desire to provide an apparatus which is capable of suppressing extension of the footprint and achieving high throughput, compared to the conventional coating/developing apparatus.